1. Field of the Disclosure
This disclosure relates to a liquid crystal display (LCD) device, and more particularly to an LCD device fabricating method capable of enhancing the reliability of the LCD device and realizing a narrow bezel panel by reducing the size of a bezel.
2. Description of the Related Art
In general, the LCD device applies data signals, corresponding to image information, to liquid crystal cells arranged in an active matrix shape and controls the transmittance of the liquid crystal cells so that the desired image is displayed. To this end, the LCD device includes an LCD panel configured to display images and a drive circuitry configured to apply driving signals to the LCD panel.
The LCD panel includes first and second glass substrates combined with each other with a fixed space therebetween and a liquid crystal layer with an anisotropic dielectric constant interposed between the first and second glass substrates. Such an LCD panel displays a desired image by controlling the quantity of transmitting light through the adjustment of an electrical field which is applied to the liquid crystal layer with the anisotropic dielectric constant.
The first glass substrate (a thin film transistor array substrate) includes a plurality of gate lines, a plurality of data lines, a plurality of pixel electrodes, and a plurality of thin film transistors. The gate lines are arranged in a direction on the first glass substrate in such a manner as to be separate by a fixed interval from one another. The data lines are arranged in another direction perpendicular to the arranged direction of the gate lines in such a manner as to be separate by a fixed interval from one another. The pixel electrodes are formed in pixel regions which are defined by the gate and data lines crossing each other, respectively. The thin film transistors are switched by signals on the respective gate lines and transfer signals on the respective data lines to the respective pixel electrodes.
The second glass substrate (a color filter substrate) includes a black matrix layer, red, green and blue color filter layers, and a common electrode. The black matrix layer is used to shield light in the rest portion of the second glass substrate without the pixel regions. The red, green and blue color filter layers are used to realize a variety of colors. The common electrode is used for realizing an image.
The first and second glass substrates are combined with each other by a sealant in such a manner as to have a fixed space provided by spacers therebetween. Then, the liquid crystal layer is formed between the first and second substrates.
As such, the LCD device sequentially applies a turning-on signal to the gate lines, and supplies data signals to the data lines whenever the turning-on signal is applied, thereby displaying a desired image on the LCD panel.
The LCD panel is prepared by combining first and second glass substrates spaced from each other with a fixed distance using a sealant and forming the liquid crystal layer between the two substrates. The first glass substrate has a margin area. As such, the first glass substrate has a wider area than that of the second glass substrate. A gate pad portion connected to the gate lines and a data pad portion connected to the data lines are formed in the margin area of the first glass substrate that is not overlapping with the second glass substrate.
In order to maintain a cell gap between the combined first and second glass substrates, the sealant is hardened using ultraviolet (UV) light. Then, the combined glass substrates are cut and processed in units of LCD panel.
Meanwhile, in order to minimize a bezel area, a scribe-on-seal method is proposed which irradiates a laser beam on the sealant and cuts the combined substrates. In other words, the scribe-on-seal method performs a burning process by focusing a laser beam on the sealant before the cutting process.
However, the range of wavelengths being absorbed by the sealant is limited. As such, it is necessary to provide a high-energy laser beam to the burning process.
More specifically, the sealant is formed from transparent acrylic and epoxy based materials, and hardened into a light gray solid through the irradiation of UV light. If the burning process using a laser beam is performed for the hardened sealant with the light gray color, the laser beam must have a high energy (or a high power). This results from the fact that the wavelength range being absorbed into the light gray sealant is limited.
If the burning process using the high energy laser beam is performed before the process of cutting the second glass substrate, the circumference of a cutting plane can be damaged due to heat being generated by the high energy laser beam. Also, the sealant can also be damaged. Due to this, reliability of the LCD device can deteriorate.